| 摘要 |
PURPOSE:To omit fall back and other error restoring procedures to be performed subsequently to the fall back, by discontinuing the communication of a transmitter without waiting for the result of the fall back, when a denying response is sent back from the receiver side. CONSTITUTION:MODEMs for high speed 6T and 6R, MODEMs for low speed 7T and 7R, control devices for the MODEMs 8T and 8R, and change-over switches 9T and 9R of the MODEMs are installed on a transmitter 5T and receiver 5R, respectively. When a trouble occurs in the printer of the receiver 5R, the control device 8R detects this. The control device 8T at the transmission side changes over the contact of the change-over switch 9T and the transmitter 5T is switched to the low-speed MODEM 7T. The high-speed MODEM 6R of the receiver 5R detects a carrier stage and, when a specific time is reached, the control device 8R switches the receiver 5R to the low-speed MODEM 7R through the switch 9R. An enquiry request for the state is outputted from the transmitter 5T to the receiver 5R, and, when a trouble signal is sent back, the data transmission is discontinued. |
